Environment Canada has issued an extreme cold alert for Waterloo region and Wellington County.
The agency says that an arctic air mass is bringing frigid temperatures on Tuesday night which are expected to stay until Friday morning.
Overnight low temperatures of between -20 C and -25 C will combine with wind gusts of between 50-70 km/h to produce windchill values between -30 and -35.
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Environment Canada says people should bundle up to avoid frostbite which will settle in quickly in these conditions.
They are also reminding people of the need to keep animals indoors in frigid weather.
The agency has also issued a “blowing snow” advisory for northern Wellington County.
The area could see some lake-effect snow and with winds as high as 60 km/h, this may create poor visibility.
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Environment Canada says visibility could be near zero at times.
The conditions are expected to persist through Wednesday and possibly right into Thursday.